WA60pts求助，玄关

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m,x[1000005],a[1000005],money;
struct sea_subway{
	ll t,b,c;
}s[1000005];
signed main(){
	cin>>n>>m;
	for(int i=1;i<=m;i++)
		cin>>x[i];
	for(int i=2;i<=m;i++)
	{
		if(x[i]>x[i-1])a[x[i-1]]++,a[x[i]]--;	
		else a[x[i-1]]--,a[x[i]]++;
	}
	for(int i=2;i<=m;i++)
		a[i]+=a[i-1];
//	for(int i=1;i<=m;i++)
//		cout<<a[i]<<' ';
	for(int i=1;i<n;i++)
	{
		cin>>s[i].t>>s[i].b>>s[i].c;
		if(s[i].c+s[i].b*a[i]<=s[i].t*a[i])money+=s[i].c+s[i].b*a[i];
		else money+=s[i].t*a[i];
	}
	cout<<money;
	return 0;
}